This project will analyze how coevolution between plants and insects shapes the web of interactions among species in contrasting ecosystems. This project will address one of the current major challenges in biology, which is how and why the same groups of species interact in different ways in different ecosystems. The specific goal is to understand how groups of interacting species diverge genetically and ecologically as they coevolve and expand their geographic ranges into new environments. The study will use interactions between a group of common plant species in western North America and a group of insect species that are the major herbivores and pollinators of those plants. DNA sequencing and related molecular methods will be used to evaluate how populations of these interacting species are genetically connected across ecosystems. The second part of the work will combine field observations of the use of flowers by the different insect species with measurements of floral morphology to assess whether the traits of these interacting plants and animals differ geographically. This will provide a test of the geographic mosaic theory of coevolution, which predicts that the strength of matching of floral trait to insect species varies with the presence of competing species of both the plant and insect. The third part of the work will use laboratory experiments to quantify the mechanisms by which natural selection shapes floral traits differently in the different ecosystems.
Collectively, these genetic and ecological studies will contribute to a broader understanding of how the web of life is organized spatially across ecosystems, and whether there are predictable patterns in how networks of interacting species change under different environmental conditions. A deeper understanding of the organization of species networks is crucial to predicting the consequences of climate change, and to conserving and restoring the biological integrity of ecosystems. This award will also support the training of graduate and undergraduate students and a postdoctoral fellow in interdisciplinary research at the interface of ecology and evolution.
